In communication based on the CDMA (Code Division Multiple Access) system excessively raised transmission power of a communication terminal device may cause, by its nature, large interference with signals sent by other users, and excessively lowered transmission power may make signals non-discriminatable as being buried in interference among communication terminal devices, only to fail in sending the signals to a base station as a destination.
For this reason, communication is established by appropriately controlling, on the base station side, transmission power using a transmission power control signal (referred to as “TPC (Transmitter Power Control)”, hereinafter), so as to enable reception of signals from the individual communication terminal devices.
There has been proposed a technique of reducing mean transmission power, when reception error of a symbol other than a pilot symbol is detected in the process of controlling transmission power based on results of comparison between a result of measurement of reception quality of a pilot symbol in a received symbol and a target value for reception quality, by configuring a communication device on the reception side taking part in control so as to elevate the target value for reception quality, typically by an error detection unit for pilot symbol reception detecting an error in reception of the pilot symbol based on a known pilot symbol pattern, and an upstream TPC symbol generation unit performing transmission power control based on not only transmission power control based on result of comparison of reception quality, but also on result of detection of reception error of pilot symbol (see Patent Document 1, for example).    [Patent Document 1] Japanese Laid-Open Patent Publication No. 2005-328355